In various open, endoscopic, and/or laparoscopic surgeries, for example, it may be desirable to coagulate, seal, and/or fuse tissue. One method of sealing tissue relies upon the application of energy, such as electrical energy, for example, to tissue captured or clamped within an end-effector or an end-effector assembly of a surgical instrument in order to cause thermal effects within the tissue. Various mono-polar and bi-polar radio frequency (Rf) surgical instruments and surgical techniques have been developed for such purposes. In general, the delivery of Rf energy to the captured tissue can elevate the temperature of the tissue and, as a result, the energy can at least partially denature proteins within the tissue. Such proteins, such as collagen, for example, can be denatured into a proteinaceous amalgam that intermixes and fuses, or seals, together as the proteins renature. As the treated region heals over time, this biological seal may be reabsorbed by the body's wound healing process.
In certain arrangements of a bi-polar radiofrequency (Rf) surgical instrument, the surgical instrument can comprise opposing first and second jaws, wherein each jaw can comprise an electrode. In use, the tissue can be captured between the jaws such that energy can flow between the electrodes in the opposing jaws and through the tissue positioned therebetween. Such instruments may have to seal many types of tissues, such as anatomic structures having walls with irregular or thick fibrous content, bundles of disparate anatomic structures, substantially thick anatomic structures, and/or tissues with thick fascia layers such as large diameter blood vessels, for example. With particular regard to sealing large diameter blood vessels, for example, such applications may require a high strength tissue seal immediately post-treatment.
The foregoing discussion is intended only to illustrate various aspects of the related art and should not be taken as a disavowal of claim scope.